Question

I know #2 is D. I just need to know why

Answer 1

Explanation

The rate law depends on coefficients in the rate-determining step of this reaction (the slowest step). The equation A + 2 B → C represents the overall reaction. Finding the rate law requires experimental data.  

Compare row 1 and row 2:

• [A]₀ is the same in row 2 and row 1;
• [B]₀ is twice as much in row 2 as in row 1;
• Rate of change in [C] is four times as much in row 2 as in row 1.

• 2² = 4. As a result, the reaction is of second order with respect to B.

Compare row 1 and row 3:

• [A]₀ is twice as much in row 3 as in row 1;
• [B]₀ is the same in row 3 and row 1;
• Rate of change in [C] is twice as much in row 3 as in row 1.

• 2¹ = 2. As a result, the reaction is of first order with respect to A.

What would be the rate law of this reaction?

Rate = k · [A] · [B]².

Answer 2

B^2 would not be b*2.